Paul Allen, co-founder of Microsoft, passed away on Monday at age 65. The billionaire died from non-Hodgkin’s lymphoma, a cancer of the lymphatic system.

Both Allen and Bill Gates founded Microsoft in 1975 after the two met at school in Seattle. Allen left the company in 1982 when he was diagnosed with the disease. However, he stayed on the board of directors.

Allen was known for his philanthropic work in addition to creating the world’s largest personal computing system.

He founded organizations such as a space transportation company, Stratolaunch, the Allen Institute for Artificial Intelligence and another institute focused on bioscience. Vulcan was another business Allen founded to manage his business ventures and philanthropy.

At the time of his death, Allen was worth $20.3 billion. He donated $2 billion to various charities over the success of his career.

He played an important part in the Pacific Northwest by purchasing two sports teams: the NBA Portland Trail Blazers and the NFL Seattle Seahawks.

NFL Commissioner Roger Goodell said Allen, “worked tirelessly alongside our medical advisers to identify new ways to make the game safer and protect players from unnecessary risk.”

Allen also loved music. He was inspired to start playing the guitar after listening to “Are You Experienced” by the Jimi Hendrix Experience, according to a 2013 interview with Guitar Player.

In 1995, the Hendrix family was imbued in a legal battle to retain rights of Hendrix’s image and music. Allen loaned the family money to cover court costs. He went on to fund the Museum of Pop Culture with $100 million.

His work didn’t stop there. He pledged #100 million to fight Ebola virus in 2014. He pledged $30 million to house Seattle’s homeless population.

Recently, Allen helped fund and build the world’s largest plane. Paul Levy, editor at large at Wired Magazine, recently profiled Allen’s efforts in building the plane.

“He and his partner Bill Gates [were] instrumental in pushing the needle and helping make all the things happen that we’re talking about today,” Levy said. “His imprint will be on all of us.”